Ink ducts are known for the nib of a fountain pen. Such ducts generally consist of a plastic cylindrical element and are provided with a plurality of circumferential grooves, defining respective fins, and with a longitudinal groove approximately 1 mm deep and 0.1-0.15 mm wide providing the channel through which ink is fed to the nib.
The longitudinal groove in question, which doesn't extend along the entire length of the duct and substantially ends at the juncture of the application zone of the nib, is formed during the moulding operation by positioning a laminar insert, of corresponding dimensions, internally of the mold.
These known ink ducts present certain drawbacks, and in particular:
a constructionally laborious method of fashioning the longitudinal groove, due to the small dimensions of the laminar insert, which can become displaced during injection of the plastic material; and PA1 a certain difficulty in utilizing multiple impression moulds, likewise due to the small dimensions of the laminar inserts which are subject to varying pressures.